SD900 DNG files unusable

Although I'm new to CHDK (great hack!) I am using it successfully on the SD700, SD850, SD890, SD900, SD950 as well as G12. However, I cannot make it work on my SD900 (Firmware GM1.00C). CHDK records a DNG file, but the file contains only bright pink slanted horizontal lines (see attached sample). Also, I am unable to create badpixel.bin. Each attempt results in: "badpixel.bin failed. Please try again."

The original DNG file is 12,409 KB (DNG4PS2 does not recognize it). The attached file is a downsized JPG version of the original DNG.

The original DNG file is 12,409 KB (DNG4PS2 does not recognize it). The attached file is a downsized JPG version of the original DNG.

That looks like the DNG doesn't contain valid image data. This can happen in some modes like the reduced resolution "low light" or "high ISO" or "iso3200" modes. On some cameras it also happens in auto mode and HQ burst mode, but I think the SD900 is too old to be affected.

It's also possible there is a bug in the port which causes CHDK to save the wrong data sometimes, but it looks like the person who made the port spent some effort on this and thought it was working.

If you can upload an actual DNG somewhere (dropbox, google drive), we can look for other problems.

edit:Actually, looking at the port it appears the DNG active area is defined incorrectly (larger than the sensor area O_o). Please upload a full DNG somewhere.